1. Field of the Invention
The present invention relates to a laser tool, and more particularly to a laser tool that is useful in measuring an angle and for projecting a laser line onto a surface at a predetermined angle from the longitudinal axis of the laser tool.
2. Description of the Related Art
Professional carpenters and homeowners alike frequently need to measure angles and draw chalk lines onto surfaces so that the material can be cut to the measured angle. One situation in particular where people need to measure angles is when cutting drywall, or paneling, to complete the wall of room having a cathedral ceiling. Certainly it will be appreciated that there are many more situations for which the measurement of an angle is necessary. However, for illustrative purposes, this situation in particular will be described.
Several methods have been used in order to determine and cut drywall at a desired angle. Perhaps the simplest way is to make an estimate, or guess. This however, may lead to unintended problems and inefficiencies. For example, the person may guess that an angle is larger than it really is. In such an event, the person would have to re-cut the drywall to a more appropriate size. This is both time consuming and wasteful. Alternatively, the person may guess that an angle is smaller than it really is. In such an event, the person will cut the drywall to too small of angle. The person will then need to cut a new sheet of drywall having more appropriate dimensions, or will need to use an undesired amount of drywall compound to complete the task. The process of cutting additional sheets of drywall is wasteful. Using more effort and drywall compound than necessary to finish a wall is both wasteful and time consuming.
Given the inherent drawbacks associated with guessing, some people use a conventional protractor to assist them in determining the angle between the ceiling and the wall. This method works well for its intended purpose. However, it is not without some limitations in its own regard. For example, a conventional protractor typically has relatively short arms that intersect at a pivoted connection. The arms can be used to contact two surfaces from which the angle there between needs determining. Yet, sometimes there are not two surfaces for which to contact the arms against. Also, the angle at the intersection of two surfaces may not be accurate of the true angle between the two surfaces a given distance from the intersection.
Still further, when using the conventional protractor, the user must still mark a chalk line or manually draw a cut line onto the surface of a piece of material to be cut. When the angle is even slightly incorrect, the error in the cut line will become more significant as the length of the line increases. Such an event can become prevalent when cutting sheets of material measuring 4 feet by 8 feet. Also, a person can forget or become confused as to the proper angle to be cut. Further, the confusion can become more likely to occur if the person is to remember multiple angles. Of course, the person can write down the angles. However, the person must carry a writing utensil and paper or an alternative writing surface if they elect to write angles down.
A further limitation of conventional protractors is that a person can bump or move one arm with respect to the other. This could happen before the person reads the angle, causing the person to misread the proper angle. Further, frequent blows or even a substantial single blow could cause damage to the arms or rotatable pivot.
A device is sold by Kell-Strom under the model PRO 360/3600 Digital Protractor and KS5589 Laser Modul Attachment. This Kell-Strom device purports to allow for defining distant angles, reference datums, sectional planes and waterlines. This product may work well for its intended purposes, but it is not without limitations. For example, the Kell-Strom device has a body with a laser being emitted from one end of the body, and has an arm that is rotatably connected to the body at one end of the bottom of the body. One limitation is that it may be difficult to use the Kell-Strom device in tight spaces, such is in attics to find the angles of the truss.
A further limitation of the Kell-Strom device is, like conventional protractors, that the arm may be damaged if it is hit. This could lead to both inaccurate readings and premature failure of the device.
A still further limitation of the Kell-Strom device is that the laser projects a beam from an end of the body. It appears that the laser projects from a plane that is between the plane in which the front lies in and the plane in which the back lies in. It appears that it is not possible to abut the Kell-Strom device against the side of an object to be cut in order to project a line onto the surface of the object to be cut. Apparently, the person needs to lift the device to an appropriate level to allow the laser to mark a line across the top surface of an adjacent piece of material. Such a limitation causes less than optimal stability and can lead to inaccurate results.
A still further limitation yet of the Kell-Strom device is that the laser projects from a point remote from the axis of rotation of the arms. Such a limitation could manifest itself when attempting to determine a cut line relatively close to the axis of rotation, when the laser is more distal than the desired start of the cut line.
A still further limitation yet of the Kell-Strom device is that it is unidirectional. The device can only be used to determine angles that lie in one direction away from the main body. Coupled with the size limitations, the person may have difficulty using the Kell-Strom device in certain applications. Further, the arm in the Kell-Strom device is incapable of a full 360 degrees of rotation relative to the body.
Thus there exists a need for a laser tool that solves these and other problems.